Lead compound



Patented Nov. 10, 1931 UNITED STATES PATENT OFFICE STERLING HENRY DIGGS AN D FRANK S. CAMPBELL, F CASPER, WYOMING; ASSIGNORS TO STANDARD OIL COMPANY, OF WRITING, INDIANA, CORPORATION OF INDIANA LEAD COMPOUND No Drawing. Application filed August 9, 1928. Serial No. 298,623.

' 1o perature with agitation until the This invention relates to lead compounds of the type which are used particularly for incorporating in certain classes of lubricants,

and which are usually called lead soaps.

5 In the usual method of manufacturing such soaps fatty oil consisting exclusively or largely of fatty acid glycerides is employed. Litharge (PbO) is mixed with the fatty oil and the whole is maintained at the high temlitharge enters into combination.

Heretofore it has been the usual procedure to supply litharge to the extent of 3 molecular proportions to 2 molecular proportions I 16 of the fatty oil, since the only lead soaps which are known in. the literature are expressed by the formula (RCOO) Pb. We have now discovered that soaps of this type are not produced to any considerable 20 extent by the interaction of litharge and fatty oils when processed as above described except to the extent that the oil contains free fatty acid. We have found that the fatty acid glyceride is not saponified in the usual way, 35 which is shown by the fact that substantially no glycerin or aldehydes are produced. The interaction between the glyceride and the litharge appears to be one of addition whereby 3 molecules of litharge become combined with a molecule of tri-glyceride to give a compound which we believe to be of the compositionexnressed bv the empirical formula: (RCOO) C H .(PbO) This fact has been established practically by analyzing lead soaps produced from neutral fatty oils in the manner described above, such analysis showing that approximately one-half of the fatty oils has been converted into lead compounds of this type while the other one-half remains substantially unchanged. Tests have shown that no glycerine is'liberated and that no aldehydes are produced. Thus in the previous method of making lead soaps the result is a mixture of lead compounds admixed with about one-half of the original fatty oil. According to the. present invention we avoid the effectual waste of about one-half 50 the fatty oils by increasing the quantity of tri-glyceride.

.mula given abo litharge substantially above the amount heretofore used, that is 3 molecular proportions of litharge to 2 molecular proportions of the ular proportions of litharge to each molecular proportion of tri-glyceride although we may employ somewhat less litharge. Where the fatty oil contains free fatty acid we employ additional litharge for the purpose of converting the free acid into lead soaps of the type expressed in the first forve. When manner the compound becomes excessively stiff and effective agitation becomes difficult or practically impossible. Accordingly we prefer to employ a suitable diluent, which may suitably be a hydrocarbon oil of relatively low viscosity and of such low volatility that it is not substantially evaporated during the manufacture of thelead compounds. In practice we prefer to employ a hydrocarbon oil of viscosity similar tothat of the fatty oil employed and we prefer to use such oil 1n approximately the same amount by volume as the fatty oil so that we produce a product which is similar in consistency and in lead compound content to the lead soaps heretofore produced. Such a product can be used as an ingredient in lubricants in the same manner as the product of the prior process without modification of proportions.

ItWill be understood that the present invention is applicable to the production of lead compounds from various fatty oils. Among those which have been used are darkpressed fish oil, winter-bleached fish oil, mixed fish oils and soy bean oil.

In making the soap. the oil is diluted as indicated above, first heating to about 300 F. and a small part of the litharge is added with efiicient stirring. When the reaction begins, which is shown by the disappearance of the yellow color due to the presence of litharge, the litharge is added at a more rapid-rate and the whole ismaintained at about the temperature indicated until the reaction is com plete. This usually takes about one hour. Loweu temperatures may be employed but the reaction is" slower. The temperature We prefer to employ 3 molecoperating in this should not exceedabout 325 F. for the best results.

The appropriate amount of lead oxide which should be employed with any suitable oil can readily be calculated from the free acidity of the oil and the saponification numher.

P r n Lead compound Neutral fat 1.60 Paraffin oil 22.33

For the purpose of comparison a soap. is made from the same oil with the quantity of litharge ordinarily employed hertofore, that is, about one-half the quantity used in the preceding example.- No diluent oil is employed. 7 5.2 pounds of the fish oil were caused to react with 27 .5 pounds of litharge under the same conditions. The analysis of the resulting product is as follows:

- 1 r ent Lead compound 36 .46 Neutral fat "32.94;

While the invention has been described with reference to the details of a specific ex ample and specific conditions of operation, it is to be understood that the invention is not intended to be limited to such details or conditions, except in so far as included in the accompanying claims.

What we regard as new, and desire to secure by Letters Patent, is:

1. The method of making lead soap compounds which consists in causing litharge to react with fatty oils, said litharge'being substantially in. excess of 3 molecular proportions to 2'molecular proportions of the fatty oil.

2. The method of producing lead soap compounds which consists in causing reaction between litharge and fatty oils, the litharge bein g present to the extent f about 3 molecular proportions to each molecular proportion of fatty oil.

3. The method of producing lead soap compounds which consists in causing litharge to react upon fatty oil in the presence of a diluent, the litharge being present in amount substantially greater than 3 molecular proportions to 2 molecular proportions of fatty oil, and the diluent being present in sufiicicnt amount to maintain fluidity during the reaction.

4. The method of producing lead soap compounds which consists in causing reaction between litharge and fatty oil in the presence of a diluent, the litharge being present to the extent of about 3 molecular proportions for each molecular proportion of the fatty oil and the diluent being present in amount sufficient to maintain fluidity during the reaction.

5. The method of producing lead soap compounds which consists in causing reaction between litharge and fatty oil containing free acid, the litharge being present in amount substantially exceeding the litharge equivalent of the free acid and 3 molecular proportions of litharge to 2 molecular proportions of the unsaponified oil.

6. The method of producing lead soap compounds which consists in causing reaction between litharge and fatty oil containing free acid. in the presence of a diluent. the litharge being present in amount substantially exceeding the litharge equivalent of the free acid and 3 molecular proportions of litharge for each 2 molecular proportions of the unsaponified oil and the diluent being present in sufficient quantity to maintain fluidity during the reaction.

7. The method of producing lead soap com-' pounds which consists in causing reaction between litharge and fatty oil containing free acid. the litharge being present in amount substantially eoual to the litharge equivalent of the free acid and 3 molecular proportions of litharge to each molecular proportion of the unsaponified fatty oil.

8. The method of making lead soap compounds which consists in causing litharge to react with fatty oils at temperatures below 325 F.. said litharge being substantially in excess of 3 molecular proportions to 2 molecular proportions of the fatty oil.

9. The method of producing lead soap compounds which consists in causing reaction between lithar e and fatty oils at a temperature below 325 F.. the litharge being present to the extent of about 3 molecular proportions to ea ch molecular proportion of fatty oil.

10. The method of producing lead soap compounds which consists in causinglitharge to react upon fatty oil in the presence, of a hydrocarbon oil at a temperature below 325 F.. the litharge being present in amount substantially greater than 3 molecular proportions to 2 molecular proportions of fatty 4,

being presept" tent of about 3 molecular pro ortions foreach molecular roportion of t e fatty oil, and the hydrocar on oil bein resent in sufiicient amount to maintain flu1 ity during the reaction.

12. The method of producing lead soap compounds which consists in-causing litharge to react upon fatty oil in the resenceof a light parafiin oil, the litharge ing present in amount substantially greater than 3 molecular proportions to 2 molecular proportions of fatty oil, and the diluent being present in sufficient amount to maintain fluid ty during the reaction.

13. The method of roducing lead soap compounds which consists in heating about 45 parts of fish oil with about 22% parts of light paraflin oil to a temperature around 300 F., adding about 32 parts of litharge thereto and agitating until the litharge is digested therein.

14. A new composition of matter consisting of. lead soap compounds of fatty oils, a hydrocarbon oil diluent, said composition containingunchanged fatty oil in the proportion of less than 10% by weight of the lead soap compounds.

15. A new composition of matter comprising about of compounds of lead oxide with fatty oils. about 22% of-a paraflin oil and less than 2% of unchanged fatty oil.

'16. A new composition of matter consisting of lead soap compounds of fatty oils. and a hydrocarbon oil diluent, said composition containing unchanged fatty oil in the roportion of less than 5% by weight of t e lead soap compounds.

STERLING HENRY DIGGS. FRANK S. CAMPBELL 

